linux-kernel - [PATCH v7 5/7] OPP: Add sanity checks in _read_opp

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Message-Id: <20200424155404.10746-6-georgi.djakov@linaro.org>
Date:   Fri, 24 Apr 2020 18:54:02 +0300
From:   Georgi Djakov <georgi.djakov@...aro.org>
To:     vireshk@...nel.org, nm@...com, sboyd@...nel.org,
        robh+dt@...nel.org, rjw@...ysocki.net, saravanak@...gle.com,
        sibis@...eaurora.org
Cc:     rnayak@...eaurora.org, bjorn.andersson@...aro.org,
        vincent.guittot@...aro.org, jcrouse@...eaurora.org,
        evgreen@...omium.org, linux-pm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        georgi.djakov@...aro.org
Subject: [PATCH v7 5/7] OPP: Add sanity checks in _read_opp_key()

When we read the OPP keys, it would be nice to do some sanity checks
of the values we get from DT and see if they match with the information
that is populated in the OPP table. Let's pass a pointer of the table,
so that we can do some validation.

Signed-off-by: Georgi Djakov <georgi.djakov@...aro.org>
---
v7:
New patch.

 drivers/opp/of.c | 19 ++++++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index 978e445b0cdb..2b590fe2e69a 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -574,8 +574,8 @@ void dev_pm_opp_of_remove_table(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);
 
-static int _read_opp_key(struct dev_pm_opp *new_opp, struct device_node *np,
-			 bool *rate_not_available)
+static int _read_opp_key(struct dev_pm_opp *new_opp, struct opp_table *table,
+			 struct device_node *np, bool *rate_not_available)
 {
 	struct property *peak, *avg;
 	u32 *peak_bw, *avg_bw;
@@ -603,6 +603,12 @@ static int _read_opp_key(struct dev_pm_opp *new_opp, struct device_node *np,
 		 * opp-avg-kBps = <path1_value path2_value>;
 		 */
 		count = peak->length / sizeof(u32);
+		if (table->path_count != count) {
+			pr_err("%s: Mismatch between opp-peak-kBps and paths (%d %d)\n",
+			       __func__, count, table->path_count);
+			return -EINVAL;
+		}
+
 		peak_bw = kmalloc_array(count, sizeof(*peak_bw), GFP_KERNEL);
 		if (!peak_bw)
 			return -ENOMEM;
@@ -624,6 +630,13 @@ static int _read_opp_key(struct dev_pm_opp *new_opp, struct device_node *np,
 	avg = of_find_property(np, "opp-avg-kBps", NULL);
 	if (peak && avg) {
 		count = avg->length / sizeof(u32);
+		if (table->path_count != count) {
+			pr_err("%s: Mismatch between opp-avg-kBps and paths (%d %d)\n",
+			       __func__, count, table->path_count);
+			ret = -EINVAL;
+			goto free_peak_bw;
+		}
+
 		avg_bw = kmalloc_array(count, sizeof(*avg_bw), GFP_KERNEL);
 		if (!avg_bw) {
 			ret = -ENOMEM;
@@ -695,7 +708,7 @@ static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
 	if (!new_opp)
 		return ERR_PTR(-ENOMEM);
 
-	ret = _read_opp_key(new_opp, np, &rate_not_available);
+	ret = _read_opp_key(new_opp, opp_table, np, &rate_not_available);
 	if (ret < 0) {
 		if (!opp_table->is_genpd)
 			dev_err(dev, "%s: opp key field not found\n", __func__);